After acknowledging that its KwaZulu-Natal-based Shongweni landfill was a contributor to malodour, waste management company EnviroServ has returned to its “old way of disposing of waste”, which comprises using lime to raise the alkalinity (pH) levels at its landfill sites.

This decision, EnviroServ technical specialist Dr Johan Schoonraad explains to Engineering News, followed after communities surrounding the landfill complained about noxious fumes emanating from the landfill site.

This led to the company initiating an investigation at this site, which found that pH levels had shifted to neutral, opening the way for an environment where “bad bacteria” were able to convert sulphates into an odorous gas known as hydrogen sulphide.

EnviroServ says a study done by toxicology expert Infotox had shown that this was the only pollutant being emitted from the site. The change in pH levels was a consequence of the company’s decision in 2013 to start implementing the then new waste management measures introduced by the waste regulations.

However, owing to the increasing number of public complaints, the Department of Environmental Affairs (DEA) suspended the landfill’s operations in terms of Section 56 of the National Environmental Management: Waste Act, in April 2017.

This was enforced by a court order from the Durban High Court, which was granted to civil group Upper Highway Air.

Schoonraad laments that, despite the company’s efforts to engage the community on this issue and keep them informed regarding the progress of environmental studies, the community made the decision to litigate. “It became very difficult for us, but we continued attempts to engage – but, once you enter into litigation, it becomes a difficult exercise.”

Following two years of uncertainty surrounding the landfill site, Shongweni, after a long remediation process, was, in September, granted permission to begin accepting certain waste streams, subject to conditions set by the DEA, and in recognition of its remediation efforts.

In the interim, since the odour issue came to light, EnviroServ has undertaken a large amount of remediation work and continues to closely monitor all emissions.

In the remediation plan, the front face of the landfill has been capped to limit the escape of odours and to prevent the infiltration of rainwater. A gas extraction and treatment system, involving a bioscrubber and gas flare, was also installed.

The leachate storage tanks and stone drainage layer have also been covered and linked to the gas collection network to reduce the venting of hydrogen sulphide.

Additionally, EnviroServ made use of contaminated stormwater available on site, which it treated to a high alkalinity level, to “try to adjust the pH on our site”, explains Schoonraad.

That has raised the pH at the landfill, he adds, noting that, since remediation has been implemented, the Shongweni landfill has seen an improvement in its fugitive hydrogen sulphide emission levels.

“This is an active landfill site and we have implemented various remediation and control measures. We are constantly monitoring emissions and the situation is under control,” he avers.

In other news, Schoonraad tells Engineering News that claims of South Africa running out of landfill space are incorrect. “It’s something which I believe is misinterpreted. The commercial waste management industry is not running out of space.”

The misinterpretation, Schoonraad explains, lies with municipalities that are running out of capacity at existing landfills, and need to build new sites.

In terms of space, he believes “it wouldn’t be a major issue to find another area where another municipal landfill site could be built and operated”.

Schoonraad also commented on the debate surrounding waste-to-energy, which is a term used to describe various technologies that convert nonrecyclable waste into usable forms of energy, including heat, fuels and electricity, and which can occur through a number of processes, such as incineration, gasification, pyrolysis, anaerobic digestion and landfill gas recovery.

Schoonraad explains that, when competing against a still abundant and cheap resource like coal, it does not make sense to try to produce electricity with an expensive facility, while competing against existing infrastructure still being paid for.

Nonetheless, he believes landfills, in the South African context, are a good solution in the attempt to find a cheaper source of energy than renewable-energy implementation.

Landfill disposal, Schoonraad believes, is a solution that can deal with waste and produce cheaper energy in the form of landfill gas.